Syrian rebels are suspected of murdering a group of captured government soldiers undermining a strategic victory which gave them control of the main highway between Aleppo and Damascus.

An unverified video of the killings, believed to have been in Saraqib, shows a group of about 20 armed men wearing rebel head bands standing over at least eight captured soldiers.

One of the soldiers pleads with the militia insisting that he did not shoot anyway.

A rebel can be overheard saying "gather them together for me".

Young men, many of them already wounded, are flung into a pile and then riddled with bullets.

Fighting in Aleppo

The executions are a reminder of a similar atrocity in Aleppo in August when a group of rebels murdered local people they accused of being members of Assad’s Shabiha (ghosts) militia.

The capture of Saraqib is a significant strategic gain for the rebels. It controls the road to Damascus, and cuts the government forces main supply route to its Aleppo line.

It also severs the regime's links to Latakia, the main coastal city in the heartland of Assad's brethren in the Alawite community.

Rebel successes in the past have come from the valuable contribution of former regime soldiers who have changed sides, bringing their tactical skills with them.

Syrian refugees near the Turkish border

But recently deserters have been reluctant to contact revolutionary fighters for fear of summary execution. Last week a group of about 20 government soldiers gave themselves up in Turkey claiming asylum and saying they would not have surrendered to rebel forces for fear of retribution.

Amnesty International’s Ann Harrison, the deputy Middle East and North Africa director, said that the footage appeared to show “a potential war crime in progress”.

She said that the human rights group would continue to investigate the alleged atrocity.

The government is accused of widespread war crimes including the murder of civilians who have been found with their hands tied close to the government held air force headquarters in Aleppo.

US Secretary of State Hillary Clinton

The rebel gains, which are reported to include a 25km radius around Saraqib, have come at a time when the exiled Syrian national Council and other groups are facing international criticism for their apparent failure to unite.

Two days ahead of key talks among the opposition in Qatar, the Syrian National Council lashed out at US Secretary of State Hillary Clinton’s recent statement that it was not fully representative of the country's diverse dissident forces.

"Any discussions aimed at passing over the Syrian National Council or at creating new bodies to replace it are an attempt to undermine the Syrian revolution by sowing the seeds of division," the SNC said in a statement.

Clinton said the SNC was not representative of on-the-ground opposition forces and that it "can no longer be viewed as the visible leader of the opposition".

It is likely that Washington will be pushing for an overhaul of the opposition at a meeting in Qatar this weekend. But US influence will depend on Qatari support.

Washington contributes a pittance, and only in the form of non-lethal aid, to rebels who receive hundreds of millions of pounds in support from Qatar and Saudi Arabia, much of it donated by individuals.